JP4976002B2 - Substrate processing apparatus, substrate processing method, and recording medium - Google Patents

Description

  The present invention relates to a substrate processing apparatus, a substrate processing method, and a recording medium.

For example, in a semiconductor device manufacturing process, various processing steps are performed in which a processing chamber containing a semiconductor wafer (hereinafter referred to as a “wafer”) is placed in a low-pressure state close to a vacuum state. As an example of processing using such a low-pressure state, for example, processing for removing an oxide film (silicon dioxide (SiO ₂ )) existing on the surface of a wafer is known (see Patent Documents 1 and 2). In such a process, in a low pressure state, a mixed gas of hydrogen fluoride gas (HF) and ammonia gas (NH ₃ ) is supplied while adjusting the temperature of the wafer to a predetermined temperature, thereby converting the oxide film into a reaction product. Thereafter, the reaction product is heated and vaporized (sublimated) to be removed from the wafer.

  Generally, as a means for holding a wafer in a processing chamber that is in a low pressure state as described above, a mounting table (electrostatic chuck) that holds the wafer by electrostatic force is used. The wafer is mounted substantially horizontally with the entire lower surface in close contact with the upper surface of the mounting table, and is attracted and held on the upper surface of the mounting table by electrostatic force. In addition, means for adjusting the temperature of the mounting table, for example, a conduit for circulating a liquid adjusted to a predetermined temperature is provided, and the temperature of the mounting table is adjusted by exchanging heat with the liquid. The temperature of the wafer in contact with the upper surface of the wafer is adjusted.

US Patent Application Publication No. 2004/0182417 US Patent Application Publication No. 2004/0184792

  However, in the conventional substrate processing apparatus, particles are easily transferred from the mounting table to the lower surface of the wafer held by the mounting table, and it is necessary to clean the wafer after processing. There is also a problem that the lower surface of the wafer is easily damaged. In order to solve such problems, it is possible to reduce the contact area between the wafer and the mounting table by providing a plurality of supporting pins on the upper surface of the mounting table and supporting the lower surface of the wafer by a plurality of supporting pins. In this case, however, there is a problem that the temperature of the wafer cannot be controlled efficiently. In particular, when the processing chamber is in a low pressure state, the gas present in the gap between the wafer and the mounting table becomes dilute, and the heat transfer effect mediated by the gas cannot be obtained, so it is difficult to control the wafer temperature. It was.

  The present invention has been made in view of the above points, and even when a wafer is processed in a low-pressure state, the temperature of the wafer is efficiently controlled while preventing the adhesion of particles and damage to the wafer. It is an object to provide a substrate processing apparatus and a substrate processing method that can be adjusted. It is another object of the present invention to provide a recording medium used in such a substrate processing apparatus and a substrate processing method.

In order to solve the above problems, according to the present invention, there is provided a device for processing a substrate, a processing chamber for storing a substrate, a supply mechanism for supplying a gas to the processing chamber, and an exhaust mechanism for exhausting the processing chamber. A mounting table for mounting the substrate in the processing chamber, and a contact member that contacts the lower surface of the substrate on the upper surface of the mounting table, wherein the mounting table adjusts the temperature of the substrate In both cases, when the substrate is subjected to predetermined processing, the lower surface of the substrate is supported by the contact member, and a gap is formed between the lower surface of the substrate and the upper surface of the mounting table. The substrate is mounted, and includes a temperature controller that adjusts the temperature of the substrate supported by the abutting member by adjusting the temperature of the mounting table. The gas supply by the supply mechanism, the exhaust mechanism Exhaust and control the temperature controller A control computer for controlling the temperature of the substrate placed on the mounting table in a state in which the processing chamber is at a predetermined pressure, and the processing chamber is lower than the predetermined pressure. pressure, and have row control and, the to treatment atmosphere in which the predetermined process on the substrate is subjected, said treatment atmosphere includes hydrogen fluoride gas and the ammonia gas, the silicon dioxide present on the surface of the substrate A substrate processing apparatus is provided, wherein the substrate is transformed into a reaction product that can be vaporized by heating .

Here, the process of transforming silicon dioxide present on the surface of the substrate into a reaction product is, for example, a COR (Chemical Oxide Removal) process (chemical oxide removal process). In the COR processing, a gas containing a halogen element and a basic gas are supplied to a substrate as a processing gas, whereby an oxide film on the substrate and gas molecules of the processing gas are chemically reacted to generate a reaction product. . The gas containing a halogen element is, for example, hydrogen fluoride vapor (HF), and the basic gas is, for example, ammonia vapor (NH ₃ ). In this case, mainly ammonium fluorosilicate ((NH ₄ ) ₂ SiF ₆ ) Is produced.

Also, the control computer, when the processing chamber to a predetermined pressure, into the processing chamber by supplying the inert gas and the ammonia gas, thereby supplying the hydrogen fluoride gas into the processing chamber in which the ammonia gas is supplied Thus, the processing chamber may be controlled to be the processing atmosphere.

  The control computer may control the processing chamber to be a processing atmosphere after adjusting the temperature of the substrate and then setting the processing chamber to a pressure lower than the predetermined pressure. The predetermined pressure may be 0.5 Torr or more, and the pressure lower than the predetermined pressure may be 0.1 Torr or less. The processing time for adjusting the temperature of the substrate may be 15 seconds or more.

Further, according to the present invention, there is provided a method for processing a substrate, wherein the substrate is carried into a processing chamber, and the lower surface of the substrate is brought into contact with a contact member provided on the upper surface of the mounting table. In a state where a gap is formed between the upper surface of the mounting table, the substrate is supported by the contact member, and the temperature of the mounting table is adjusted while the processing chamber is at a predetermined pressure, adjusting the temperature of the substrate, then the processing chamber in the processing atmosphere pressure lower than the predetermined pressure, and facilities a predetermined process on the substrate, wherein the treatment atmosphere includes hydrogen fluoride gas and the ammonia gas The predetermined treatment is a treatment for transforming silicon dioxide existing on the surface of the substrate into a reaction product by reacting with the treatment atmosphere, and after the predetermined treatment, the reaction product is converted into a reaction product. Vaporization by heating And performing a substrate processing method is provided.

Also, by supplying the inert gas and ammonia gas into the processing chamber, the processing chamber to a predetermined pressure, then, by the ammonia gas is supplied to the hydrogen fluoride gas into the processing chamber which is supplied, The processing chamber may be the processing atmosphere. Further, after the temperature of the substrate is adjusted, the processing chamber may be set to a pressure lower than the predetermined pressure, and then the processing chamber is set to a processing atmosphere.

  The predetermined pressure may be 0.5 Torr or more. The pressure lower than the predetermined pressure may be 0.1 Torr or less. The processing time for adjusting the temperature of the substrate may be 15 seconds or more.

According to the present invention, there is provided a recording medium on which a program that can be executed by a control computer of the substrate processing apparatus is recorded, and the program is executed by the control computer, whereby the substrate processing apparatus Further, a recording medium is provided, characterized in that the substrate processing method according to any one of claims 7 to 12 is performed.

  According to the present invention, since the gap is provided between the lower surface of the substrate and the upper surface of the mounting table, it is possible to prevent particles from being transferred from the mounting table to the substrate or being damaged. it can. When adjusting the temperature of the substrate, the processing chamber is set to a predetermined pressure, so that gas can be supplied to the gap between the lower surface of the substrate and the chuck body, and between the substrate and the mounting table via such gas. Heat exchange can be performed. Therefore, the temperature of the substrate can be adjusted efficiently.

Hereinafter, preferred embodiments of the present invention will be described. First, the structure of a wafer that is a substrate processed by the processing method according to the present embodiment will be described. FIG. 1 is a schematic cross-sectional view of the wafer W before the etching process, and shows a part of the surface (device formation surface) of the wafer W. The wafer W is, for example, a silicon wafer having a thin plate shape formed in a substantially disc shape, and an Si (silicon) layer as a base material of the wafer W and an oxide layer (silicon dioxide) used as an interlayer insulating layer on the surface thereof. : SiO ₂ ), a Poly-Si (polycrystalline silicon) layer used as a gate electrode, and a TEOS (tetraethyl orthosilicate: Si (OC ₂ H ₅ ) ₄ ) layer as a side wall portion (side wall) made of an insulator The structure which consists of is formed. The surface (upper surface) of the Si layer is a substantially flat surface, and the oxide layer is laminated so as to cover the surface of the Si layer. The oxide layer is formed by a thermal CVD reaction using a diffusion furnace, for example. The Poly-Si layer is formed on the surface of the oxide layer, and is etched along a predetermined pattern shape. Therefore, a part of the oxide layer is covered with the Poly-Si layer and the other part is exposed. The TEOS layer is formed so as to cover the side surface of the Poly-Si layer. In the illustrated example, the Poly-Si layer has a substantially prismatic cross-sectional shape, and is formed in an elongated plate shape extending in a direction from the near side to the far side in FIG. On both the left and right side surfaces of the Poly-Si layer, the poly-Si layer is provided so as to cover from the near side to the far side and from the lower edge to the upper edge of the Poly-Si layer. And the surface of the oxide layer is exposed on both the left and right sides of the Poly-Si layer and the TEOS layer.

FIG. 2 shows the state of the wafer W after the etching process. The wafer W is subjected to, for example, dry etching after an oxide layer, a Poly-Si layer, a TEOS layer, etc. are formed on the Si layer as shown in FIG. As a result, as shown in FIG. 2, the exposed oxide layer and a part of the Si layer covered with the oxide layer are removed from the surface of the wafer W. That is, the concave portions generated by etching are formed on both the left and right sides of the Poly-Si layer and the TEOS layer. The recess is formed so as to sink from the height of the surface of the oxide layer to the Si layer, and the Si layer is exposed on the inner surface of the recess. Since the Si layer is easily oxidized, when oxygen in the atmosphere adheres to the surface of Si exposed in this way, a natural oxide film (silicon dioxide: SiO ₂ ) is formed on the inner surface of the recess.

  Next, a processing system that performs COR processing, PHT (Post Heat Treatment) processing, and SiGe layer deposition processing on the etched wafer W will be described. In the COR process, a gas containing a halogen element and a basic gas are supplied to the wafer as a process gas, so that a natural oxide film adhering to the wafer and a gas molecule of the process gas are chemically reacted to generate a reaction product. It is generated. The gas containing a halogen element is, for example, hydrogen fluoride gas, and the basic gas is, for example, ammonia gas. In this case, a reaction product mainly containing ammonium fluorosilicate is generated. The PHT process is a process for heating the wafer after the COR process and vaporizing a reaction product by the COR process.

  A processing system 1 shown in FIG. 3 includes a loading / unloading unit 2 for loading / unloading a wafer W into / from the processing system 1, a common transfer chamber 3 formed in a substantially polygonal shape (for example, hexagonal shape), and a COR processing for the wafer W. A COR processing apparatus 5 as a substrate processing apparatus (vacuum processing apparatus) according to this embodiment, a PHT processing apparatus 6 as a substrate processing apparatus that performs PHT processing on the wafer W, and a substrate that performs SiGe layer deposition processing A plurality of processing apparatuses, for example, two epitaxial growth apparatuses 7A and 7B, and a control computer 8 for giving a control command to each part of the processing system 1 are provided.

  The loading / unloading unit 2 has a transfer chamber 12 in which a first wafer transfer mechanism 11 for transferring a wafer W having a substantially disk shape, for example, is provided. The wafer transfer mechanism 11 has two transfer arms 11a and 11b that hold the wafer W substantially horizontally. On the side of the transfer chamber 12, for example, three mounting tables 13 on which a carrier C capable of storing a plurality of wafers W side by side is mounted. In addition, an orienter 14 is installed for rotating and aligning the wafer W by optically determining the amount of eccentricity.

  The transfer chamber 12 and the common transfer chamber 3 are connected to each other via two load lock chambers 20A and 20B that can be evacuated. Gate valves 21 that can be opened and closed are provided between the load lock chambers 20A and 20B and the transfer chamber 12, and between the load lock chambers 20A and 20B and the common transfer chamber 3, respectively. One of these two load lock chambers 20A and 20B (for example, the load lock chamber 20A) is used when the wafer W is unloaded from the transfer chamber 12 and loaded into the common transfer chamber 3, and the other (for example, the load lock chamber 20A). The load lock chamber 20B) may be used when the wafer W is unloaded from the common transfer chamber 3 and loaded into the transfer chamber 12.

  In the loading / unloading unit 2, the wafer W is held by the transfer arms 11 a and 11 b, and is transferred to a desired position by being rotated and linearly moved and moved up and down in a substantially horizontal plane by driving the wafer transfer device 11. . The transfer arms 11a and 11b are moved forward and backward with respect to the carrier C, the orienter 14, and the load lock chambers 20A and 20B on the mounting table 10, respectively, so that they can be carried in and out.

  In the common transfer chamber 3, a second wafer transfer mechanism 31 for transferring the wafer W is provided. The wafer transfer mechanism 31 has two transfer arms 31a and 31b that hold the wafer W substantially horizontally.

  Outside the common transfer chamber 3, a COR processing unit 5, a PHT processing unit 6, an epitaxial growth unit 7A, an epitaxial growth unit 7B, a load lock chamber 20B, and a load lock chamber 20A surround the common transfer chamber 3, for example, They are arranged in this order in the clockwise direction when viewed from above. Processing between the common transfer chamber 3 and the processing chamber 32 in the COR processing apparatus 5, between the common transfer chamber 3 and the processing chamber 33 in the PHT processing apparatus 6, and processing in the common transfer chamber 3 and the respective epitaxial growth apparatuses 7A and 7B. Between the chambers 34, gate valves 35 that can be opened and closed are provided.

  In the common transfer chamber 3, the wafer W is held by the transfer arms 31 a and 31 b and is transferred to a desired position by being rotated and linearly moved and moved up and down in a substantially horizontal plane by driving the wafer transfer mechanism 31. . Then, transfer arms 31a, 20B, 20B, a processing chamber 32 in the COR processing apparatus 5, a processing chamber 33 in the PHT processing apparatus 6, and a processing chamber 34 in each of the epitaxial growth apparatuses 7A, 7B, respectively. By advancing and retracting 31b, it can be carried into and out of each processing chamber.

  As shown in FIG. 4, the COR processing apparatus 5 includes a housing 5 a, and the inside of the housing 5 a is a processing chamber (processing space) 32 having a sealed structure in which the wafer W is stored. A loading / unloading port 36 for loading / unloading the wafer W into / from the processing chamber 32 is provided on one side surface of the housing 5a. The loading / unloading port 36 is provided with the gate valve 35 described above.

  In the processing chamber 32, a mounting table 40 is provided for mounting the wafer W in a substantially horizontal state. As shown in FIGS. 5 and 6, the mounting table 40 includes a chuck body 41 that has a substantially circular shape in plan view, and is arranged so that a substantially flat upper surface 41 a of the chuck body 41 is substantially horizontal. . A plurality of contact pins 42 as contact members that are brought into contact with the lower surface of the wafer W are provided on the upper surface 41a so as to protrude upward. In the example shown in FIG. 5, three contact pins 42 are provided, and are provided on the peripheral edge of the upper surface 41a so as to surround the central portion of the upper surface 41a. In such a configuration, the wafer W is supported substantially horizontally above the chuck body 41 in a state where the three portions of the lower peripheral edge portion are respectively placed on the upper end portions of the contact pins 42. Thus, a gap G having a predetermined width H in the height direction is formed between the lower surface of the wafer W supported by the contact pins 42 and the upper surface 41 a of the chuck body 41.

  As shown in FIG. 6, the chuck body 41 includes a base 41b fixed to the bottom of the housing 5a, and an upper layer 41c having an upper surface 41a to which a contact pin 42 is attached. The heat insulating material 41d is provided between the base portion 41b and the upper layer portion 41c.

  Further, the COR processing apparatus 5 is provided with a temperature controller 46 for adjusting the temperature of the wafer W by adjusting the temperature of the mounting table 40 (upper layer portion 41c) to a predetermined temperature. The temperature controller 46 includes a pipe 47 through which a temperature adjusting liquid (for example, water) is passed, a pump 48, and a liquid temperature adjusting unit 49 that adjusts the temperature of the temperature adjusting liquid. For example, the pipe 47 is introduced from the bottom of the housing 5a to the periphery of the mounting table 40, and inside the upper layer 41c, the center of the upper layer 41c extends from the periphery of the upper layer 41c along a predetermined rotation direction. In the central part of the mounting table 40, it is led out from the bottom of the housing 5 a to the outside. The upstream end of the pipe 47 is connected to a pump 48 provided outside the housing 5a. The liquid temperature adjusting unit 49 is interposed in the pipe line 47 outside the housing 5a. In such a configuration, the temperature adjusting liquid flows in the pipe 47 by the operation of the pump 48, is temperature-controlled in the liquid temperature adjusting unit 49, and is then supplied into the upper layer portion 41 c of the mounting table 40. Is derived from the housing 5a. Thus, while the liquid passes through the upper layer portion 41c, heat is exchanged between the upper layer portion 41c and the liquid, so that the temperature of the upper layer portion 41c is adjusted. Since a heat insulating material 41d is provided between the upper layer portion 41c and the base portion 41b, the heat insulating material 41d can prevent the heat of the upper layer portion 41c from escaping to the outside of the housing 5a. ing.

As shown in FIG. 4, the COR processing apparatus 5 is provided with a supply mechanism 50 that supplies gas to the processing chamber 32. The supply mechanism 50 includes a supply path 51 that supplies hydrogen fluoride gas (HF) as a processing gas containing a halogen element to the processing chamber 32, and a supply path 52 that supplies ammonia gas (NH ₃ ) as a basic gas to the processing chamber 32. , A supply path 53 for supplying argon gas (Ar) as an inert gas to the processing chamber 32, a supply path 54 for supplying nitrogen gas (N ₂ ) as an inert gas to the processing chamber 32, and a shower head 55. Yes. The supply path 51 is connected to a supply source 61 of hydrogen fluoride gas. The supply passage 51 is provided with a flow rate adjustment valve 62 that can open and close the supply passage 51 and adjust the supply flow rate of the hydrogen fluoride gas. The supply path 52 is connected to an ammonia gas supply source 63. The supply passage 52 is provided with a flow rate adjusting valve 64 that can open and close the supply passage 52 and adjust the supply flow rate of ammonia gas. The supply path 53 is connected to an argon gas supply source 65. The supply path 53 is provided with a flow rate adjustment valve 66 that can open and close the supply path 53 and adjust the supply flow rate of argon gas. The supply path 54 is connected to a nitrogen gas supply source 67. The supply path 54 is provided with a flow rate adjusting valve 68 capable of opening and closing the supply path 54 and adjusting the supply flow rate of nitrogen gas. These supply paths 51, 52, 53, 54 are connected to a shower head 55 provided in the ceiling of the processing chamber 32, and hydrogen fluoride gas, ammonia gas, argon, and the like from the shower head 55 to the processing chamber 32. Gas and nitrogen gas are discharged so as to diffuse.

  Further, the COR processing apparatus 5 is provided with an exhaust mechanism 71 for exhausting gas from the processing chamber 32. The exhaust mechanism 71 includes an exhaust path 75 in which an open / close valve 72 and an exhaust pump 73 for performing forced exhaust are interposed.

  4 and 6, the gate valve 35, the pump 48, the liquid temperature adjusting unit 49, the flow rate adjusting valves 62, 64, 66, 68, the on-off valve 72, the exhaust pump 73, etc. of the COR processing device 5 are provided. The operation of each part is controlled by a control command of the control computer 8. That is, the supply of hydrogen fluoride gas, ammonia gas, argon gas, nitrogen gas by the supply mechanism 50, exhaust by the exhaust mechanism 71, temperature adjustment by the temperature controller 46, and the like are controlled by the control computer 8.

Components such as the mounting table 40, the housing 5a, and the shower head 55 of the COR processing apparatus 5 are made of metal such as aluminum (Al) or aluminum alloy that has been subjected to surface treatment such as anodizing. However, when an alumite treatment is performed on the surface of such a component, metal particles such as aluminum sulfate (Al ₂ (SO ₄ ) ₃ ) are likely to be generated from the surface, and the wafer W may be contaminated. In order to reduce the generation of such metal particles, a structure using solid aluminum or aluminum nitride (AIN) that has not been subjected to surface treatment may be used. Further, for example, in the parts such as the mounting table 40 and the shower head 55, the aluminum surface covered with quartz (SiO ₂ ) or the like may be used. Also in this case, the generation of metal particles can be effectively reduced.

  As shown in FIG. 7, the PHT processing apparatus 6 includes a sealed processing chamber (processing space) 33 for storing the wafer W, and the wafer W is placed in the processing chamber 33 in a substantially horizontal manner. A mounting table 80 is provided. Although not shown, a loading / unloading port for loading / unloading the wafer W into / from the processing chamber 33 is provided, and the above-described gate valve 35 is provided at the loading / unloading port.

  The components such as the mounting table 80 of the PHT processing apparatus 6 may be made of, for example, aluminum (Al) that has been subjected to alumite treatment, or solid aluminum that has not been subjected to surface treatment. However, metal particles such as aluminum sulfate generated from the surface may be transferred to the lower surface of the wafer W by thermophoresis. In general, as the temperature of the mounting table 80 is raised to a higher temperature (for example, 160 ° C. or more), the reaction of the PHT process in the process chamber 33 is more facilitated, but the transfer of particles due to thermophoresis is also more likely to occur. For this reason, the temperature of the mounting table 80 is not set too high, for example, about 150 ° C. or less, preferably about 100 ° C. to 135 ° C. If it does so, adhesion of the particle to the wafer W can also be reduced, promoting reaction favorably.

Further, the PHT processing apparatus 6 includes a supply mechanism 82 having a supply path 81 for heating and supplying an inert gas such as nitrogen gas (N ₂ ) to the process chamber 33, and an exhaust path 83 for exhausting the process chamber 33. Is provided with an exhaust mechanism 84. The supply path 81 is connected to a nitrogen gas supply source 85. The supply path 81 is provided with a flow rate adjusting valve 86 capable of opening and closing the supply path 81 and adjusting the supply flow rate of nitrogen gas. The exhaust path 83 is provided with an open / close valve 87 and an exhaust pump 88 for forced exhaust.

  The operation of each part such as the gate valve 35, the flow rate adjusting valve 86, and the exhaust pump 88 of the PHT processing device 6 is controlled by a control command of the control computer 8.

  Each functional element of the processing system 1 is connected to a control computer 8 that automatically controls the operation of the entire processing system 1 via signal lines. Here, the functional elements include, for example, the gate valve 35, the pump 48, the liquid temperature adjusting unit 49, the flow rate adjusting valves 62, 64, 66, 68, the on-off valve 72, the exhaust pump 73, and the PHT process of the COR processing device 5 described above. It means all elements that operate to realize predetermined process conditions, such as the gate valve 35, the flow regulating valve 86, and the exhaust pump 88 of the apparatus 6. The control computer 8 is typically a general-purpose computer that can realize any function depending on the software to be executed.

  As shown in FIG. 3, the control computer 8 includes a calculation unit 8a having a CPU (central processing unit), an input / output unit 8b connected to the calculation unit 8a, and control software inserted into the input / output unit 8b. And a stored recording medium 8c. The recording medium 8c stores control software (program) that is executed by the control computer 8 to cause the processing system 1 to perform a predetermined substrate processing method to be described later. By executing the control software, the control computer 8 realizes various process conditions (for example, pressure in the processing chamber 32, etc.) defined for each functional element of the processing system 1 by a predetermined process recipe. To control. For example, for the COR processing apparatus 5, as will be described in detail later, control for adjusting the temperature of the wafer W with the processing chamber 32 kept at a predetermined pressure P2 (control for realizing step S2), processing chamber A control command is given so that steps S1 to S5 are performed in order, such as control for setting 32 to a processing atmosphere of pressure P3 (control for realizing step S4).

  The recording medium 8c may be fixedly provided in the control computer 8, or may be detachably attached to a reading device (not shown) provided in the control computer 8 and readable by the reading device. In the most typical embodiment, the recording medium 8 c is a hard disk drive in which control software is installed by a service person of the manufacturer of the processing system 1. In another embodiment, the recording medium 8c is a removable disk such as a CD-ROM or DVD-ROM in which control software is written. Such a removable disk is read by an optical reading device (not shown) provided in the control computer 8. Further, the recording medium 8c may be in any format of RAM (random access memory) or ROM (read only memory). Further, the recording medium 8c may be a cassette type ROM. In short, any medium known in the technical field of computers can be used as the recording medium 8c. In a factory where a plurality of processing systems 1 are arranged, control software may be stored in a management computer that comprehensively controls the control computer 8 of each processing system 1. In this case, each processing system 1 is operated by a management computer via a communication line and executes a predetermined process.

  Next, a processing method of the wafer W in which the processing system 1 configured as described above is used will be described. First, a wafer W having a Si layer, an oxide layer, a Poly-Si layer, and a TEOS layer as shown in FIG. 1 is etched by a dry etching apparatus or the like, and a recess in which Si is exposed as shown in FIG. Is formed. The wafer W after the dry etching process is stored in the carrier C and transferred to the processing system 1.

  In the processing system 1, as shown in FIG. 3, the carrier C in which a plurality of wafers W are stored is placed on the mounting table 13, and one wafer W is taken out from the carrier C by the wafer transfer mechanism 11. , Are loaded into the load lock chamber 20A. When the wafer W is loaded into the load lock chamber 20A, the load lock chamber 20A is sealed and decompressed. Thereafter, the load lock chamber 20A and the common transfer chamber 3 decompressed with respect to the atmospheric pressure are communicated with each other. Then, the wafer transfer mechanism 31 unloads the wafer W from the load lock chamber 20 </ b> A and loads it into the common transfer chamber 3.

  The wafer W loaded into the common transfer chamber 3 is first loaded into the processing chamber 32 of the COR processing apparatus 5. The wafer W is transferred from the wafer transfer mechanism 31 to the mounting table 40 with the surface (device formation surface) as the upper surface. When the wafer W is loaded, the loading / unloading port 36 is closed, and a series of processes including COR processing is started. The steps performed in the COR processing device 5 will be described in detail later. By the COR process, the natural oxide film in the concave portion of the wafer W is transformed into a reaction product (see FIG. 8).

  When the process in the COR processing apparatus 5 is completed, the loading / unloading port 36 is opened, and the wafer W is unloaded from the processing chamber 32 by the wafer transfer mechanism 31 and loaded into the processing chamber 33 of the PHT processing apparatus 6.

  In the PHT processing apparatus 6, the wafer W is placed in the processing chamber 33 with the surface as the upper surface. When the wafer W is carried in, the processing chamber 33 is sealed and PHT processing is started. In the PHT process, while the inside of the processing chamber 33 is exhausted by the exhaust path 83, a high-temperature heating gas is supplied into the processing chamber 33 through the supply path 81, and the inside of the processing chamber 33 is heated by the heating gas. As a result, the reaction product generated by the COR treatment is heated and vaporized, removed from the inner surface of the recess, and the surface of the Si layer is exposed (see FIG. 9). The temperature and pressure in the processing chamber 33 are controlled so as to vaporize the reaction product, and are heated to, for example, a temperature of about 100 ° C. or higher. Thus, by performing the PHT process after the COR process, the wafer W can be dry-cleaned, and the natural oxide film can be removed from the Si layer by dry etching.

  When the PHT process is completed, the supply of the heated gas is stopped and the loading / unloading port of the PHT processing device 6 is opened. Thereafter, the wafer W is unloaded from the processing chamber 33 by the wafer transfer mechanism 31 and is loaded into the processing chamber 34 of the epitaxial growth apparatus 7A or 7B.

  When the wafer W is loaded into the processing chamber 34, the processing chamber 34 is sealed and the SiGe film forming process is started. In the film forming process, the reaction gas supplied into the processing chamber 34 and the Si layer exposed in the recess of the wafer W react chemically, and SiGe is epitaxially grown in the recess (see FIG. 10). Here, since the natural oxide film is removed from the surface of the Si layer exposed in the recess by the above-described COR treatment and PHT treatment, SiGe is preferably grown on the basis of the surface of the Si layer. It is done.

  In this way, when the SiGe layers are formed in the concave portions on both sides, in the Si layer, the portion sandwiched between the SiGe layers receives compressive stress from both sides. That is, a strained Si layer having a compressive strain is formed in a portion sandwiched between the SiGe layers below the Poly-Si layer and the oxide layer.

  When the SiGe layer is thus formed and the film forming process is completed, the wafer W is unloaded from the processing chamber 34 by the wafer transfer mechanism 31 and is loaded into the load lock chamber 20B. When the wafer W is loaded into the load lock chamber 20B, after the load lock chamber 20B is sealed, the load lock chamber 20B and the transfer chamber 12 are brought into communication. Then, the wafer transport mechanism 11 unloads the wafer W from the load lock chamber 20B and returns it to the carrier C on the mounting table 13. As described above, a series of steps in the processing system 1 is completed.

Next, the process performed in the COR processing apparatus 5 will be described in detail. When the wafer W is transferred to the processing chamber 32, the wafer W transferred from the wafer transfer mechanism 31 to the mounting table 40 is mounted substantially horizontally with a plurality of contact pins 42 contacting the lower peripheral edge of the wafer W. Placed. In this state where the lower surface is supported by the contact pins 42, the wafer W is separated upward from the upper surface 41 a of the mounting table 40, and a gap G is formed between the lower surface of the wafer W and the upper surface 41 a. The Incidentally, when carrying the wafer W into the processing chamber 32, the pressure of the processing chamber 32 is a pressure P1 near vacuum state is decompressed from the atmospheric pressure P _O.

When the wafer W is loaded into the processing chamber 32 and delivered to the mounting table 40, the processing chamber 32 is sealed, and then ammonia gas, argon gas, and nitrogen gas are supplied to the processing chamber 32 from the supply paths 52, 53, and 54, respectively. To do. As a result, the inside of the processing chamber 32 is pressurized from the initial pressure P1 when the wafer W is loaded to a predetermined pressure P2 (for example, about 2 Torr (about 2.67 × 10 ² Pa), P1 <P2 < _PO ). (Step S1 in FIGS. 11 and 12).

  When the inside of the processing chamber 32 reaches a predetermined pressure P2, the supply of ammonia gas, nitrogen gas, and argon gas is stopped, and then the temperature controller 46 sets the temperature of the wafer W to a predetermined target value (for example, about 25 ° C.). (Step S2). When the temperature of the wafer W is adjusted, the liquid is passed through the conduit 47, and the temperature of the upper layer portion 41c of the mounting table 40 is adjusted to a predetermined temperature. Here, although the lower surface of the wafer W is close to the upper surface 41a, it is separated with a gap G, but ammonia gas, argon gas, and nitrogen gas are introduced into the processing chamber 32 in advance. Thus, the mixed gas enters the gap G. Therefore, even if the wafer W is not in direct contact with the upper surface 41a, heat exchange is performed between the wafer W and the upper surface 41a via the mixed gas in the gap G. It is possible to effectively approach the temperature of 41a. Therefore, by adjusting the temperature of the upper layer portion 41c while the processing chamber 32 is at the pressure P2, the heat (cold heat) of the upper layer portion 41c is transferred to the wafer W via the mixed gas, and the temperature of the wafer W is increased. Can be adjusted reliably.

  When the temperature control of the wafer W is completed, the inside of the processing chamber 32 is forcibly evacuated, and the processing chamber 32 is evacuated to a pressure P3 lower than the pressure P2 (eg, about 0.1 Torr (about 13.3 Pa) or less, P1 <P3). The pressure is reduced to <P2) (step S3). When the pressure in the processing chamber 32 becomes stable and reaches the pressure P3, hydrogen fluoride gas is supplied from the supply path 51 to the processing chamber 32. Here, since ammonia gas is supplied to the processing chamber 32 in advance, by supplying hydrogen fluoride gas, the atmosphere of the processing chamber 32 is changed to a processing atmosphere containing hydrogen fluoride gas and ammonia gas. COR processing (step S4) is started for W. Under such a low-pressure processing atmosphere, the natural oxide film present on the surface of the wafer W is chemically reacted with the hydrogen fluoride gas molecules and the ammonia gas molecules to be converted into reaction products. During the COR process, the atmosphere in the processing chamber 32 is maintained at a constant pressure P3.

  If the pressure in the processing chamber 32 is reduced to stabilize at the pressure P3 before supplying the hydrogen fluoride gas in this way, the pressure of the processing atmosphere can be easily stabilized, and the fluorination in the processing atmosphere can be stabilized. The uniformity of the concentration of hydrogen gas or ammonia gas can be improved. Therefore, processing unevenness of the wafer W can be prevented. Moreover, although hydrogen fluoride gas has the property of being easily liquefied and easily adhering to the inner wall of the housing 5a, it is possible to suppress the occurrence of such a problem by supplying it immediately before the COR processing.

  When the COR processing is completed, the processing chamber 32 is forcibly exhausted again and the pressure is reduced to the pressure P1 (step S5). Thereby, hydrogen fluoride gas and ammonia gas are discharged from the processing chamber 32. Thereafter, the loading / unloading port 36 is opened, the wafer W is unloaded, and the next unprocessed wafer W is loaded into the processing chamber 32.

  According to the COR processing apparatus 5, the gap G is formed between the lower surface of the wafer W and the upper surface 41 a of the mounting table 40, thereby preventing particles from being transferred from the mounting table 40 to the wafer W. it can. In addition, the wafer W can be prevented from being damaged by the lower surface of the wafer W rubbing against the upper surface of the mounting table 40 and particles. When adjusting the temperature of the wafer W, the inside of the processing chamber 32 is pressurized to a predetermined pressure P2, so that a mixed gas is supplied to the gap G between the lower surface and the upper surface 41a of the wafer W. As a medium, heat can be efficiently transferred between the wafer W and the mounting table 40. Therefore, the temperature of the wafer W can be adjusted efficiently.

  The preferred embodiments of the present invention have been described above, but the present invention is not limited to such examples. It is obvious for those skilled in the art that various changes and modifications can be conceived within the scope of the technical idea described in the claims. It is understood that it belongs to.

  In the above embodiment, the COR processing apparatus 5 and the processing method using the COR processing apparatus 5 are exemplified as the substrate processing apparatus and the substrate processing method for processing a substrate in a low pressure state. However, the present invention includes such an apparatus and method. Without being limited thereto, the present invention can also be applied to other substrate processing apparatuses and substrate processing methods, for example, a substrate processing apparatus and a substrate processing method for performing, for example, an etching process, a CVD process, etc. on a substrate. Further, the substrate is not limited to a semiconductor wafer, and may be a glass for an LCD substrate, a CD substrate, a printed substrate, a ceramic substrate, or the like.

  In the present embodiment, argon gas and nitrogen gas are exemplified as the inert gas supplied to the processing chamber 32. However, the present invention is not limited thereto, and for example, only argon gas may be used. The inert gas may be any other inert gas, for example, helium gas (He) or xenon gas (Xe), or argon gas, nitrogen gas, helium gas, or xenon gas. Of these, a mixture of two or more gases may be used.

  In the above embodiment, gas is supplied from the surroundings to the gap G between the wafer W and the mounting table 40 by supplying gas from the supply paths 52, 53, 54 to the processing chamber 32. Although it is configured to supply, a supply port that supplies gas directly to the gap G may be provided. For example, a supply port for discharging an inert gas such as helium (He) or nitrogen gas is provided on the upper surface 41 a of the mounting table 40, and the supply port is not connected to the lower surface of the wafer W mounted on the mounting table 40. It is good also as a structure which can supply active gas.

  The temperature controller 46 is configured to adjust the temperature by flowing a temperature adjusting liquid into the mounting table 40, but is not limited to such a configuration, for example, an electric heater that heats the mounting table 40 by resistance heat, or , A configuration including a halogen lamp heater for heating the mounting table 40 by radiant heat may be used. Also in this case, the wafer W can be heated by heating the mounting table 40 with an electric heater or a halogen lamp heater.

The present inventors examined various conditions of the processing steps in the COR processing apparatus 5. The target value of the temperature of the wafer W in step S2 may be about 10 ° C. or more and 60 ° C. or less, for example. The processing time for adjusting the temperature of the wafer in step S2 may be about 15 seconds or more and about 300 seconds or less. The longer the temperature control processing time, the closer the wafer temperature can be to the target value. However, in consideration of the throughput and productivity of the entire processing system 1, it is desirable that the wafer temperature be shorter, for example, about 30 seconds or less. The pressure P2 in the processing chamber 32 may be a value of about 0.5 Torr (about 66.7 Pa) to about 100 Torr (13.3 × 10 ³ Pa). The higher the pressure P2, the more efficiently the temperature of the wafer can be controlled. However, considering the structural restrictions of the COR processing apparatus 5 and the like, for example, about 4 Torr (about 5.33 × 10 ² Pa) or less may be used. Would be desirable. In steps S1 to S4, when various gases are supplied, the supply flow rate of hydrogen fluoride gas is about 500 sccm (about 8.45 × 10 ⁻¹ m ³ / s) or less, and the supply flow rate of ammonia gas is about 500 sccm. Hereinafter, the supply flow rate of argon gas may be about 2000 sccm (about 3.38 m ³ / s) or less, and the supply flow rate of nitrogen gas may be about 2000 sccm or less.

In addition, the present inventors examined the pressure dependence in the temperature control of the wafer in step S2. FIG. 13 shows the relationship between the pressure P2 in the processing chamber 32 and the wafer temperature when the processing time in which the temperature of the wafer is adjusted in step S2 is a constant value (30 seconds). The temperature of the upper surface 41a of the mounting table 40 was 25 ° C., and the temperature of the wafer before temperature adjustment was 35 ° C. As shown in FIG. 13, when the pressure P2 is 0.9 Torr (about 1.20 × 10 ² Pa), 2 Torr, 4 Torr (about 5.33 × 10 ² Pa), the wafer temperature is about 29.48 ° C., respectively. , About 27.91 ° C. and about 27.32 ° C. were obtained. Therefore, it was demonstrated that the higher the pressure P2, the more efficiently the temperature of the wafer can be controlled.

  In addition, the present inventors investigated the time dependency in wafer temperature control in step S2. FIG. 14 shows a relationship between the wafer processing temperature and the wafer temperature when the pressure P2 is set to a constant value (2 Torr) in step S2. The temperature of the upper surface 41a of the mounting table 40 was 25 ° C., and the temperature of the wafer before temperature adjustment was 35 ° C. As shown in FIG. 14, when the processing time is 15 seconds, 30 seconds, and 60 seconds, the temperature of the wafer is cooled to about 29.13 ° C., about 27.91 ° C., and about 26.90 ° C., respectively. Obtained. Therefore, it was demonstrated that the longer the processing time, the closer the wafer temperature approaches the target value (25 ° C.).

  The present invention can be applied to a substrate processing apparatus, a substrate processing method, and a recording medium provided in the substrate processing apparatus for processing a substrate in a low pressure state.

It is the schematic longitudinal cross-sectional view which showed the structure of the surface of the wafer before etching a Si layer. It is the schematic longitudinal cross-sectional view which showed the structure of the surface of the wafer after etching the Si layer. It is a schematic plan view of a processing system. It is the schematic longitudinal cross-sectional view which showed the structure of the COR processing apparatus. It is a top view of a mounting base. It is a schematic longitudinal cross-sectional view of a mounting base. It is the schematic longitudinal cross-sectional view which showed the structure of the PHT processing apparatus. It is the schematic longitudinal cross-sectional view which showed the state of the surface of the wafer after COR process. It is the schematic longitudinal cross-sectional view which showed the state of the surface of the wafer after PHT processing. It is the schematic longitudinal cross-sectional view which showed the state of the surface of the wafer after a SiGe layer film-forming process. It is the flowchart which showed the procedure of the process in a COR processing apparatus. It is the graph which showed the pressure change of the processing chamber during processing in a COR processing device. It is the graph which showed the relationship between the pressure of a process chamber, and the temperature of a wafer when the processing time which adjusted the temperature of the wafer was 30 seconds. It is the graph which showed the relationship between the processing time which temperature-controlled the wafer, and the temperature of a wafer when a pressure was set to 2 Torr in step S2.

Explanation of symbols

W wafer 1 processing system 5 COR processing device 6 PHT processing device 8 control computer 8a arithmetic unit 8c recording medium 32 processing chamber 33 processing chamber 40 mounting table 41 chuck body 41a upper surface 42 abutting pin 46 temperature controller 47 conduit 50 supply mechanism 51 Hydrogen fluoride gas supply path 52 Ammonia gas supply path 53 Argon gas supply path 54 Nitrogen gas supply path 71 Exhaust mechanism 75 Exhaust path

Claims (13)

An apparatus for processing a substrate,
A processing chamber for storing the substrate, a supply mechanism for supplying gas to the processing chamber, and an exhaust mechanism for exhausting the processing chamber;
The processing chamber includes a mounting table on which a substrate is mounted,
Provided on the top surface of the mounting table is a contact member that can contact the bottom surface of the substrate,
The mounting table supports the lower surface of the substrate by the contact member both when the temperature of the substrate is adjusted and when the substrate is subjected to a predetermined treatment, and the lower surface of the substrate, the upper surface of the mounting table, The substrate is placed in a state where a gap is formed between
A temperature controller for adjusting the temperature of the substrate supported by the contact member by adjusting the temperature of the mounting table;
A control computer for controlling the temperature controller by supplying gas by the supply mechanism, exhausting by the exhaust mechanism, and the temperature controller;
The control computer controls the temperature of the substrate placed on the mounting table in a state where the processing chamber is set to a predetermined pressure, and sets the processing chamber to a pressure lower than the predetermined pressure and the substrate. said predetermined process have line control and a to a processing atmosphere to be applied to,
The processing atmosphere contains hydrogen fluoride gas and ammonia gas, and changes the silicon dioxide present on the surface of the substrate into a reaction product that can be vaporized by heating. Processing equipment. The control computer supplies an inert gas and an ammonia gas to the processing chamber when the processing chamber is set to a predetermined pressure,
  The substrate processing apparatus according to claim 1, wherein the processing chamber is controlled to be the processing atmosphere by supplying hydrogen fluoride gas to the processing chamber to which the ammonia gas is supplied. The control computer, after adjusting the temperature of the substrate, controls the processing chamber to be a processing atmosphere after setting the processing chamber to a pressure lower than the predetermined pressure. 2. The substrate processing apparatus according to 2. The substrate processing apparatus according to claim 1, wherein the predetermined pressure is 0.5 Torr or more. 5. The substrate processing apparatus according to claim 1, wherein a pressure lower than the predetermined pressure is 0.1 Torr or less. The substrate processing apparatus according to claim 1, wherein a processing time for adjusting the temperature of the substrate is 15 seconds or more. A method of processing a substrate, comprising:
Bring the substrate into the processing chamber,
The lower surface of the substrate is brought into contact with an abutting member provided on the upper surface of the mounting table, and the substrate is supported by the abutting member in a state where a gap is formed between the lower surface of the substrate and the upper surface of the mounting table. ,
Adjusting the temperature of the substrate by adjusting the temperature of the mounting table with the processing chamber at a predetermined pressure,
Then, the processing chamber is set to a processing atmosphere at a pressure lower than the predetermined pressure, and the substrate is subjected to a predetermined processing,
The treatment atmosphere includes hydrogen fluoride gas and ammonia gas,
The predetermined treatment is a treatment for transforming silicon dioxide present on the surface of the substrate into a reaction product by reacting with the treatment atmosphere,
A substrate processing method , wherein after the predetermined treatment is performed, the reaction product is vaporized by heating . By supplying an inert gas and ammonia gas to the processing chamber, the processing chamber is brought to a predetermined pressure,
  The substrate processing method according to claim 7, wherein after that, the processing chamber is set to the processing atmosphere by supplying hydrogen fluoride gas to the processing chamber to which the ammonia gas is supplied. 9. The substrate processing method according to claim 7, wherein after the temperature of the substrate is adjusted, the processing chamber is set to a pressure lower than the predetermined pressure, and then the processing chamber is set to a processing atmosphere. The substrate processing method according to claim 7, wherein the predetermined pressure is 0.5 Torr or more. The substrate processing method according to claim 7, wherein a pressure lower than the predetermined pressure is 0.1 Torr or less. The substrate processing method according to claim 7, wherein a processing time for adjusting the temperature of the substrate is 15 seconds or more. A recording medium on which a program that can be executed by a control computer of a substrate processing apparatus is recorded,
  13. The recording medium according to claim 7, wherein the program is executed by the control computer to cause the substrate processing apparatus to perform the substrate processing method according to any one of claims 7 to 12.

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